Form I-129F, Petition for Alien Fiancé(e) (uscis.gov)
8. Evidence for Petitions to Classify a Fiancé(e) as a K-1 Nonimmigrant In addition to the evidence described above, you must submit evidence of: A. Intention to Marry Within 90 Days of Entry. Submit evidence that you and your fiancé(e) intend to marry within 90 days of your fiancé(e)’s entry as a K-1 nonimmigrant. Evidence of your intention to marry may include statements of intent to marry signed by both you and your fiancé(e) or any other evidence that establishes, by a preponderance of the evidence, your mutual intention; and
B. In-Person Meeting. Submit evidence that you and your fiancé(e) met in person during the 2-year period immediately before you filed this petition. Evidence of this meeting may include, but is not limited to, a written statement from you and/or your fiancé(e) stating the circumstances of your meeting, a copy of airline tickets, passport pages, or other evidence. If you believe you qualify for an exception to the in-person meeting requirement, submit evidence in support of the exception. If you claim that the in-person meeting requirement would result in extreme hardship to you, submit evidence to support your claim. If you claim that the in-person meeting requirement would violate strict and long-established customs of your fiancé(e)’s foreign culture or social practice, include evidence that any and all aspects of the traditional arrangements have been or will be met in accordance with the custom or practice.